Die-to-die electrical isolation in a semiconductor package

ABSTRACT

Some of the embodiments of the present disclosure provide a semiconductor package comprising a first die; a second die; and an inductor arrangement configured to inductively couple the first die and the second die while maintaining electrical isolation between active circuit components of the first die and active circuit components of the second die. Other embodiments are also described and claimed.

CROSS REFERENCE TO RELATED APPLICATIONS

The present disclosure is a continuation of and claims priority to U.S. patent application Ser. No. 12/817,944, filed Jun. 17, 2010, now U.S. Pat. No. 8,564,091, issued Oct. 22, 2013, which claims priority to U.S. Provisional Patent Application No. 61/223,325, filed Jul. 6, 2009, which is incorporated herein by reference.

TECHNICAL FIELD

Embodiments of the present invention relate to electrical circuits in general, and more specifically, to achieving die-to-die electrical isolation in a semiconductor package.

BACKGROUND

The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventor, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

FIG. 1 schematically illustrates a semiconductor package 100. The semiconductor package 100 includes a first die 108 a and a second die 108 b, both attached to a die frame 104. The first die 108 a includes a plurality of die pads 110 a, . . . , 110 f and the second die 108 b includes a plurality of die pads 112 a, . . . , 112 d.

The semiconductor package 100 includes a plurality of pins 116 a, . . . , 116 e, electrically coupled to the plurality of die pads 110 a, . . . , 110 e, respectively, using bond wires 124 a, . . . , 124 e. The semiconductor package 100 also includes a plurality of pins 118 a, . . . , 118 c, electrically coupled to the plurality of die pads 112 a, . . . , 112 c, respectively, using bond wires 126 a, . . . , 126 c. One or more pins (e.g., pins 120 a and 120 b) of the semiconductor package 100 may not be electrically coupled to any die pad 110 a, . . . , 110 e.

In various applications, it may be desirable to transmit a signal from the first die 108 a to the second die 108 b, and/or from the second die 108 b to the first die 108 a. This is possible, for example, by electrically coupling die pad 110 f of the first die 108 a with the die pad 112 d of the second die 108 b using bond wire 128. Although not illustrated in FIG. 1, the die pads 110 f and 112 d may also be electrically coupled, using one or more bond wires, via one or more pins of the semiconductor package 100 (e.g., instead of or in addition to directly coupling the die pads 110 f and 112 d using bond wire 128).

In some applications, the two dies 108 a and 108 b may operate at different voltages. For example, the first die 108 a may operate at a voltage that is relatively higher than an operating voltage of the second die 108 b. In some of these applications (e.g., when a difference between the operating voltages of the two dies are relatively high), it may be desirable to electrically isolate the two dies. Accordingly, in these applications, it may not be desirable to electrically couple the two dies 108 a and 108 b. However, it is still desirable to transmit signals between the two dies 108 a and 108 b.

SUMMARY

In various embodiments, the present disclosure provides a semiconductor package comprising a first die; a second die; and an inductor arrangement configured to inductively couple the first die and the second die while maintaining electrical isolation between active circuit components of the first die and active circuit components of the second die.

In various embodiments, the present disclosure also provides a method of transmitting signals between a first die and a second die included in a semiconductor package, the method comprising providing an inductor arrangement that inductively couples the first die and the second die, while maintaining electrical isolation between active circuit components of the first die and active circuit components of the second die, wherein the inductor arrangement includes a first inductor circuit and a second inductor circuit; transmitting a first signal from the first die through the first inductor circuit such that a second signal is inductively generated in the second inductor circuit; and receiving the second signal in the second die, wherein the second signal is representative of the first signal.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed description, reference is made to the accompanying drawings which form a part hereof wherein like numerals designate like parts throughout, and in which is shown by way of illustration embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of embodiments in accordance with the present invention is defined by the appended claims and their equivalents.

FIG. 1 schematically illustrates an exemplary semiconductor package;

FIG. 2 schematically illustrates a semiconductor package, in accordance with various embodiments of the present disclosure;

FIGS. 3A and 3B schematically illustrate cross sectional views of a first die of the semiconductor package of FIG. 2, in accordance with various embodiments of the present disclosure;

FIG. 4 schematically illustrates an attachment of a first die and a second die to a die frame of the semiconductor package of FIG. 2, in accordance with various embodiments of the present disclosure;

FIGS. 5A-5B schematically illustrate respective semiconductor packages in which two dies are attached to two different die frames, in accordance with various embodiments of the present disclosure;

FIGS. 6A-6C schematically illustrate respective semiconductor packages in which no bond wires are used between two dies attached to two different die frames, in accordance with various embodiments of the present disclosure;

FIG. 7 illustrates a method for transmitting signals between a first die and a second die included in a semiconductor package, in accordance with various embodiments of the present disclosure; and

FIG. 8 illustrates another method for transmitting signals between a first die and a second die included in a semiconductor package, in accordance with various embodiments of the present disclosure.

FIGS. 9 and 10 illustrate two methods for transmitting signals between a first die and a second die included in a semiconductor package, in accordance with various embodiments of the present disclosure.

DETAILED DESCRIPTION

In the following detailed description, reference is made to the accompanying drawings which form a part hereof wherein like numerals designate like parts throughout, and in which is shown by way of illustration embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of embodiments is defined by the appended claims and their equivalents.

Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding embodiments of the present invention; however, the order of description should not be construed to imply that these operations are order dependent.

The description may use the phrases “in an embodiment,” or “in embodiments,” which may each refer to one or more of the same or different embodiments. The phrase “in some embodiments” is used repeatedly. The phrase generally does not refer to the same embodiments; however, it may. The terms “comprising,” “having,” and “including” are synonymous, unless the context dictates otherwise. The phrase “A and/or B” means (A), (B), or (A and B). The phrase “A/B” means (A), (B), or (A and B), similar to the phrase “A and/or B.” The phrase “at least one of A, B and C” means (A), (B), (C), (A and B), (A and C), (B and C) or (A, B and C). The phrase “(A) B” means (B) or (A and B), that is, A is optional.

FIG. 2 schematically illustrates a semiconductor package 200, in accordance with various embodiments of the present disclosure. The semiconductor package 200 includes a first die 208 a and a second die 208 b, both attached to a die frame 204.

Although the semiconductor package 200 includes one or more pins, one or more die pads in the dies 208 a and 208 b, and/or one or more bond wires coupling one or more die pads in the dies 208 a and/or 208 b to one or more pins, some of these components are not illustrated in FIG. 2 for the purpose of clarity and to avoid obfuscating teaching principles of the present disclosure.

The first die 208 a includes a plurality of connectors 210 a, 210 b, 210 c and 210 d, and the second die 208 b includes a plurality of connectors 212 a, 212 b, 212 c and 212 d. In various embodiments, each of the connectors 210 a, 210 b, 210 c and 210 d of the first die 208 a are electrically coupled to corresponding connectors 212 a, 212 b, 212 c and 212 d of the second die 208 b through respective bond wires 220 a, 220 b, 220 c and 220 d, as illustrated in FIG. 2. In various embodiments, the connectors 210 a, . . . , 210 d comprise die pads of the first die 208 a, and the connectors 212 a, . . . , 212 d comprise die pads of the second die 208 b.

The connectors 210 b and 210 c of the first die 208 a are electrically coupled using an interconnect 224 a, and the connectors 212 a and 212 d of the second die 208 b are electrically coupled using an interconnect 224 b. In FIG. 2, the interconnects (e.g., interconnects 224 a and 224 b) are illustrated using checkered lines for the purpose of clarity and to better distinguish the interconnects from various other components of the semiconductor package 200. The interconnects 224 a and 224 b comprise any suitable electrically conductive material, including, for example, any suitable metal interconnection or wires.

The first die 208 a also includes terminals A and A′. The terminal A is electrically coupled to the connector 210 a through a connection 228 a, and the terminal A′ is electrically coupled to the connector 210 d through a connection 228 b. The second die 208 b also includes terminals B and B′. The terminal B is electrically coupled to the connector 212 b through a connection 228 c, and the terminal B′ is electrically coupled to the connector 212 c through a connection 228 d. In FIG. 2, the connections 228 a, . . . , 228 d are illustrated using grey lines for the purpose of clarity and to better distinguish the connects from various other components of the semiconductor package 200. The connections 228 a, . . . , 228 d comprise any suitable electrically conductive material, e.g., any appropriate metal.

It should be noted that the connections 228 c and 228 d are electrically isolated from the interconnect 224 b. For example, the connections 228 c and 228 d may lie in a plane of the second die 208 b that is different from a plane in which the interconnect 224 b lies, and the connections 228 c and 228 d may be electrically isolated from the interconnect 224 b using any appropriate insulating material (not illustrated in FIG. 2).

Although not illustrated in FIG. 2, the first die 208 a includes a plurality of active circuit components (e.g., one or more electrical components (e.g., logic gates, transistors, etc.), one or more metal layers associated with electrical component(s), die pads, any component that is configured to receive, transmit and/or process electrical signals, and/or the like). For the purpose of this disclosure and unless otherwise noted, it is assumed that the active circuit components of the first die 208 a do not include the connectors 210 a, . . . , 210 d. Also, for the purpose of this disclosure and unless otherwise noted, as the interconnect 224 a is not a part of the first die 208 a, it is assumed that the active circuit components of the first die 208 a do not include the interconnect 224 a. Similarly, although not illustrated in FIG. 2, the second die 208 b includes a plurality of active circuit components. For the purpose of this disclosure and unless otherwise noted, it is assumed that the active circuit components of the second die 208 b do not include the connectors 212 a, . . . , 212 d. Also, for the purpose of this disclosure and unless otherwise noted, as the interconnect 224 b is not a part of the second die 208 b, it is assumed that the active circuit components of the second die 208 b do not include the interconnect 224 b.

Although not illustrated in FIG. 2, the terminals A and A′ may be electrically coupled to one or more active circuit components of the first die 208 a. Thus, the connections 228 a and 228 b, bond wires 220 a and 220 d, and the interconnect 224 b are electrically coupled to one or more active circuit components of the first die 208 a through terminals A and A′.

Although not illustrated in FIG. 2, the terminals B and B′ may be electrically coupled to one or more active circuit components of the second die 208 b. Thus, the connections 228 c and 228 d, bond wires 220 b and 220 c, and the interconnect 224 a are electrically coupled to one or more active circuit components of the second die 208 b through terminals B and B′.

The bond wires 220 a and 220 d, the connectors 212 a and 212 d, and the interconnect 224 b are electrically isolated from the active circuit components of the second die 208 b. For example, the interconnect 224 b may be a floating wire in the second die 208 b. Similarly, the bond wires 220 b and 220 c, the connectors 210 b and 210 c, and the interconnect 224 a are electrically isolated from the active circuit components of the first die 208 a. For example, the interconnect 224 a may be a floating wire in the first die 208 a.

FIG. 3A schematically illustrates a cross sectional view of the first die 208 a of the semiconductor package 200 of FIG. 2, in accordance with various embodiments of the present disclosure. Also illustrated in FIG. 3A is the interconnect 224 a of FIG. 2. The first die 208 a is illustrated by dotted lines to clarify that, in various embodiments, the interconnect 224 a may not be a part of the first die 208 a. In the embodiments of FIG. 3A, the interconnect 224 a is electrically isolated from active circuit components of the first die 208 a. The first die 208 a includes a Silicon Dioxide (SiO₂) layer 334, under which other layers and components 338 (e.g., one or more active circuit components) of the first die 208 a are formed. To further electrically isolate the interconnect 224 a from the active circuit components of the first die 208 a, an insulating layer 330 is formed over the SiO₂ layer 334. The insulating layer 330 comprises any suitable electrically insulating material, e.g., a suitable type of polymide. Thus, the interconnect 224 a is separated from the active circuit components of the first die 208 a by at least the insulating layer 330 and the SiO₂ layer 334.

In various embodiments, the interconnect 224 a is separated from other metal layers and active circuit components of the first die 208 a by at least a first distance. The first distance is based in part on a breakdown voltage of the insulating layer 330 and the SiO₂ layer 334, and/or a voltage level of signals transmitted through the interconnect 224 a. For example, the first distance may be determined such that the first distance is sufficient to prevent an electrical breakdown of the insulating layer 330 and the SiO₂ layer 334 while signals are being transmitted through the interconnect 224 a. In various embodiments, the first distance may be equal to about 10 micron.

Although not illustrated in FIG. 3A, similar to the interconnect 224 a, the interconnect 224 b of the second die 208 b is also electrically isolated from metal layers and active circuit components of the second die 208 b at least using a suitable insulating layer and SiO₂ layer. The interconnect 224 b is separated from other metal layers and active circuit components of the second die 208 b by at least a second distance. The second distance is based in part on a breakdown voltage of the insulating layer and the SiO₂ layer in the second die 208 b, and/or a voltage level of signals transmitted through the interconnect 224 b. In various embodiments, the second distance may be equal to about 10 micron.

FIG. 3B schematically illustrates another cross sectional view of the first die 208 a of the semiconductor package 200 of FIG. 2, in accordance with various embodiments of the present disclosure. Also illustrated in FIG. 3B is the bond wire 220 b. The first die 208 a is illustrated by dotted lines to clarify that, in various embodiments, the bond wire 220 b may not be a part of the first die 208 a. In the embodiments of FIG. 3B, the connector 210 b is electrically isolated from active circuit components of the first die 208 a. The first die 208 a includes a SiO₂ layer 334 b (which may be similar to the SiO₂ layer 334 of FIG. 3A), under which other layers and components 338 b (e.g., one or more active circuit components) of the first die 208 a are formed. To further electrically isolate the connector 210 b from the active circuit components of the first die 208 a, an insulating layer 330 b is formed over the SiO₂ layer 334 b. In various embodiments, the insulating layer 330 b may be similar to the insulating layer 330 of FIG. 3A. Thus, the connector 210 b is separated from one or more active circuit components of the first die 208 a by at least the insulating layer 330 b and the SiO₂ layer 334 b. In various embodiments, the connector 210 b is separated from other metal layers and active circuit components of the first die 208 a by at least a third distance that is based in part on a breakdown voltage of the insulating layer 330 b and the SiO₂ layer 334 b, and/or a voltage level of signals transmitted through the connector 210 b. For example, the third distance may be sufficient to prevent an electrical breakdown of the insulating layer 330 b and the SiO₂ layer 334 b while signals are being transmitted through the connector 201 b. In various embodiments, the third distance may be equal to about 10 micron.

Similarly, the other connectors (e.g., connectors 210 a, 210 c, 210 d, 212 a, . . . , 212 d) are separated from metal layers and active circuit components of the respective dies by at least respective minimum distances, which are based in part on a breakdown voltage of the respective insulating layers and the SiO₂ layers, and/or voltage levels of signals transmitted through the respective connectors.

FIG. 4 schematically illustrates an attachment of the first die 208 a and the second die 208 b to the die frame 204 of the semiconductor package 200 of FIG. 2, in accordance with various embodiments of the present disclosure. FIG. 4 illustrates a cross sectional view of the semiconductor package 200. As illustrated in FIG. 4, the first die 208 a is attached to the die frame 204 using a die attach glue layer 412. The second die 208 b is attached to the die frame 204 using a first die attach glue layer 420 a, an electrical insulation layer 416, and a second die attach glue layer 420 b. Die attach glue layers 412, 420 a and/or 420 b are electrically and/or thermally conductive, and comprise any suitable die attach glue (e.g., silver adhesive paste). In various embodiments, the first die 208 a is electrically coupled to the die frame 204 through electrically conductive die attach glue layer 412.

The electrical insulation layer 416 may be thermally conductive, but has relatively higher electrical resistance, thereby electrically isolating the second die 208 b from the die frame 204. The electrical insulation layer 416 comprises any suitable electrically insulating material, such as glass or polymide.

Although not illustrated in FIG. 4, in various other embodiments, instead of using the first die attach glue layer 420 a, the electrical insulation layer 416, and the second die attach glue layer 420 b, the second die 208 b may be attached to the die frame 204 using a die attach glue layer (e.g., comprising an epoxy resin) that is electrically nonconductive.

Referring to FIGS. 2 and 4, since the second die 208 b is electrically isolated from the die frame 204 (e.g., because of the electrical insulation layer 416), the first die 208 a and the second die 208 b are not electrically coupled through the die frame 204. Furthermore, as previously described, the bond wires 220 a and 220 d, the connectors 212 a and 212 d, and the interconnect 224 b of FIG. 2 are electrically isolated from the active circuit components of the second die 208 b. Similarly, the bond wires 220 b and 220 c, the connectors 210 b and 210 c, and the interconnect 224 a are electrically isolated from the active circuit components of the first die 208 a. Accordingly, the active circuit components of the first die 208 a and the active circuit components of the second die 208 b are not electrically coupled through any of the bond wires 220 a, . . . , 220 d, the interconnects 224 a and 224 b, the connectors 210 a, . . . , 210 d, 212 a, . . . , 212 d and/or the connections 228 a, . . . , 228 d. Accordingly, the active circuit components of the first die 208 a and the active circuit components of the second die 208 b are not electrically coupled, either through the die frame 204 or through the bond wires 210 a, . . . , 210 d. That is, the active circuit components of the two dies 208 a and 208 b are electrically isolated.

Referring again to FIG. 2, in the semiconductor package 200, the bond wire 220 a is placed proximally to the bond wire 220 b, and the bond wire 220 c is placed proximally to the bond wire 220 d. In various embodiments, the bond wire 220 a, the interconnect 224 b and the bond wire 220 d form a first inductor circuit. Similarly, the bond wire 220 b, the interconnect 224 a and the bond wire 220 c form a second inductor circuit. Thus, the first inductor circuit is formed across terminals A and A′, and the second inductor circuit is formed across terminals B and B′. In various embodiments, due to the close proximity of the bond wire 220 a and bond wire 220 b, and close proximity of the bond wire 220 c and the bond wire 220 d, an inductive coupling develops between the first inductor circuit and the second inductor circuit. The first inductor circuit and the second inductor circuit, in combination, act as a transformer, with one of the first inductor circuit and the second inductor circuit acting as a primary winding of the transformer, and another of the first inductor circuit and the second inductor circuit acting as a secondary winding of the transformer.

Thus, in various embodiments, the semiconductor package 200 includes an inductor arrangement (comprising the first inductor circuit and the second inductor circuit) configured to inductively couple the first die 208 a and the second die 208 b, and to inductively transmit signals between the first die 208 a and the second die 208 b, while maintaining electrical isolation between active circuit components of the first die 208 a and the active circuit components of the second die 208 b.

For example, in various embodiments, an input signal is transmitted between terminals A and A′ in the first die 208 a (i.e., transmitted through the first inductor circuit comprising the bond wire 220 a, the interconnect 224 b and the bond wire 220 d). The input signal may be a relatively high frequency signal (e.g., with narrow pulse width, with high frequency modulation, and/or the like). Because of the mutual inductance between the first inductor circuit and the second inductor circuit, an output signal is generated (e.g., induced) in the second inductor circuit (e.g., generated or induced in the bond wires 220 b and/or 220 c) based at least in part on the input signal being transmitted in the first inductor circuit (e.g., transmitted in bond wires 220 a and/or 220 d). The output signal is representative of the input signal (e.g., proportional to the input signal), and is received across terminals B and B′. Thus, the input signal is inductively transmitted from the first die 208 a to the second die 208 b, while maintaining electrical isolation between the active circuit components of the first die 208 a and the active circuit components of the second die 208 b. In various embodiments, such inductive coupling of the two dies 208 a and 208 b, while maintaining electrical isolation between the active circuit components of the two dies 208 a and 208 b, allows the two dies 208 a and 208 b to operate at different voltage levels with respect to each other. For example, a voltage level of the signal handled by the first die 208 a may be different (e.g., relatively higher) than a voltage level of the signal handled by the second die 208 b.

The second die 208 b can also transmit a signal to the first die 208 a through the inductive arrangement. For example, an input signal is transmitted between terminals B and B′ in the second die 208 a (i.e., transmitted through the second inductor circuit comprising the bond wire 220 b, the interconnect 224 a and the bond wire 220 c). The input signal may be a relatively high frequency signal. Because of the mutual inductance between the first inductor circuit and the second inductor circuit, an output signal is generated (e.g., induced) in the first inductor circuit (e.g., generated or induced in bond wires 220 a and/or 220 d) based at least in part on the input signal being transmitted in the second inductor circuit (e.g., transmitted in the bond wires 220 b and/or 220 c). The output signal is representative of the input signal (e.g., proportional to the input signal), and is received across terminals A and A′. Thus, the input signal is inductively transmitted from the second die 208 b to the first die 208 a, while maintaining electrical isolation between the active circuit components of the first die 208 a and the active circuit components of the second die 208 b.

Bi-directional signal transmission (e.g., signal transmission from the first die 208 a to the second die 208 b, and from the second die 208 b to the first die 208 a) can also be achieved using the inductor arrangement of FIG. 2. Such bi-directional signal transmission can be achieved using, for example, time division multiplexing. For example, during a first plurality of time slots, signals are transmitted from the first die 208 a to the second die 208 b, and during a second plurality of time slots signals are transmitted from the second die 208 b to the first die 208 a, where the second plurality of time slots are interleaved with the first plurality of time slots.

Bi-directional signal transmission can also be achieved, for example, by appropriately modulating signals using different frequencies. For example, a first signal having a first frequency may be transmitted from the first die 208 a to the second die 208 b, while a second signal having a second frequency (which is different from the first frequency) may be transmitted from the second die 208 b to the first die 208 a. As the frequencies of the first signal and the second signal are different, the two signals may be transmitted substantially simultaneously (or at least in an overlapping manner), resulting in substantially simultaneous bi-directional signal transmission between the first die 208 a and the second die 208 b.

In various embodiments, signals transmitted between the two dies 208 a and 208 b are parity protected, so that any error originating during the inductive transfer of signals between the dies 208 a and 208 b can be corrected at a later stage. The inductance between the two inductor circuits may be relatively low. To overcome effects of such low inductance, relatively high frequency signals (e.g., with narrow pulse width, with high frequency modulation, and/or the like) may be transmitted between the two dies 208 a and 208 b.

Although only four bond wires 220 a, . . . , 220 d are illustrated to form the inductor arrangement in FIG. 2, in various other embodiments, any other number of bond wires (e.g., two, six, eight, or the like) may also be used to form an inductor arrangement to inductively transmit signals between the first die 208 a and the second die 208 b, while maintaining electrical isolation between the active circuit components of the first die 208 a and the active circuit components of the second die 208 b.

As previously noted herein, the bond wire 220 a is placed proximally to the bond wire 220 b, and the bond wire 220 c is placed proximally to the bond wire 220 d. For example, bond wires 220 a and 220 b may be placed sufficiently close such that signals in any one of the bond wires 220 a and 220 b may have an inductive effect in another of the bond wires 220 a and 220 b (e.g., generate or induce current in another of the bond wires). Similarly, bond wires 220 c and 220 d may be placed sufficiently close such that signals in any one of the bond wires 220 c and 220 d may have an inductive effect in another of the bond wires 220 c and 220 d.

If the bond wires 220 a and 220 b (and/or bond wires 220 c and 220 d) are located too close to each other, there may be an electrical breakdown between the bond wires 220 a and 220 b (and/or bond wires 220 c and 220 d). However, as the bond wires 220 a, . . . , 220 d (as well as the dies 208 a and 208 b) are molded in a package mold (which may be, for example, a plastic enclosure) having relatively high electrical insulating properties, the breakdown voltage between the bond wires 220 a and 220 b (and/or bond wires 220 c and 220 d) increases, thereby allowing the bond wires 220 a and 220 b (and/or bond wires 220 c and 220 d) to be located sufficiently close to each other such that one of the bond wires has an inductive effect on the other.

In FIG. 2, the dies 208 a and 208 b are attached to a single die frame 204. However, in various other embodiments, the dies 208 a and 208 b may be attached to different die frames. FIG. 5A schematically illustrates a semiconductor package 500 in which two dies are attached to two different die frames, in accordance with various embodiments of the present disclosure. Various components of the semiconductor package 500 of FIG. 5A are at least in part similar to the respective components of the semiconductor package 200 of FIG. 2. However, unlike the semiconductor package 200 (where the dies 208 a and 208 b are attached to a single die frame 204), the semiconductor package 500 includes a first die frame 204 a and a second die frame 204 b. The first die 208 a and the second die 208 b are attached to the respective die frames 204 a and 204 b.

In the semiconductor package 500, as the two dies 208 a and 208 b are attached to separate die frames, the two dies 208 a and 208 b cannot be electrically coupled through a common die frame. Accordingly, in various embodiments, one or both of the dies 208 a and 208 b may be attached to the respective die frames 204 a and 204 b using a thermally and/or electrically conductive glue layer (e.g., in a manner similar to the way the first die 208 a is attached to the die frame 204 in FIG. 4).

FIG. 5B illustrates another semiconductor package 510 in which an edge 204 c-1 of a first die frame 204 c is inside of an edge 208 c-1 of a first die 208 c. In other words, the edge 204 c-1 does not extend beyond the edge 208 c-1. Similarly, an edge 204 d-1 of a second die frame 204 d is also inside of an edge 208 d-1 of a second die 208 d. By having the edges 204 c-1 and 204 d-1 of the first and second die frames 204 c and 204 d behind the respective edges 208 c-1 and 208 d-1 of the first and second dies 208 c and 208 d, the first and second dies 208 c and 208 d can be moved closer to each other vis-à-vis the first and second dies 208 a and 208 b as shown in FIG. 5A, thereby shortening the lengths of the bond wires 220 a-d there between. Based on the disclosure and teachings provided herein, it should be understood that, in other embodiments, the edge of a first die frame may be located behind the edge of a corresponding first die, while the edge of a second die frame may be located beyond the edge of a corresponding second die.

FIG. 6A illustrates a semiconductor package 600 in which no bond wires are used to physically connect a first die 608 a and a second die 608 b, in accordance with various embodiments. The first die frame 604 a and the second die frame 604 b are separated by a gap 630 which provides electrical isolation. The first die frame 604 a includes the first die 608 a. The first die 608 a further includes terminals A and A′. There is a circuit or signal path between terminals A and A′ formed by connection 628 a, connector 610 b, interconnect 624 b, connector 610 d, bond wire 620 a, connector 610 a, interconnect 624 a, connector 610 c and connection 628 b. The connections 628 a, 628 b, the connectors 610 a, 610 b, 610 c, 610 d, the interconnect 624 a, 624 b and the bond wire 620 a are similar to those elements as shown in FIGS. 2 and 5. The bond wire 620 a is generally disposed above a surface of the first die 608 a with its two ends connected to connectors 610 a, 610 d. In one configuration, the bond wire 620 a forms a half-loop between connectors 610 a and 610 d. The second die 608 b includes elements that are similar to those of the first die 608 a. Similarly, there is also a circuit or signal path between terminals B and B′. The respective circuit paths between terminals A and A′ and B and B′ effectively constitute an inductor arrangement that inductively or magnetically couples the first and second dies 608 a, 608 b. When a signal is transmitted along one circuit path, a corresponding signal is inductively created in the other circuit path, and vice versa, thereby allowing the first die 608 a and the second die 608 b to communicate.

FIG. 6B illustrates another semiconductor package 660 in which no bond wires are used to physically connect a first die 668 a and a second die 668 b, in accordance with various embodiments. The first die frame 664 a and the second die frame 664 b are similar to the first die frame 604 a and the second die frame 604 b as shown in FIG. 6A. Similar to the first die frame 604 a as shown in FIG. 6A, the first die frame 664 a includes the first die 668 a. The first die 668 a further includes terminals C and C′. There is a circuit or signal path between terminals C and C′ formed by connection 628 a, connector 610 b, bond wire 620 c, connector 610 d, interconnect 624 e, connector 610 a, bond wire 620 d, connector 610 c and connection 628 b. The bond wires 620 c, 620 d are generally disposed above a surface of the first die 668 a with their two ends connected to connectors 610 b, 610 d and 610 a, 610 c respectively. In one configuration, the bond wires 620 c and 620 d each form a half-loop between connectors 610 b, 610 d and connectors 610 a, 610 c respectively. The second die 668 b includes elements that are similar to those of the first die 668 a. Similarly, there is also a circuit or signal path between terminals D and D′. The respective circuit paths between terminals C and C′ and D and D′ effectively constitute an inductor arrangement that inductively or magnetically couples the first and second dies 668 a, 668 b. When a signal is transmitted along one circuit path, a corresponding signal is inductively created in the other circuit path, and vice versa, thereby allowing the first die 668 a and the second die 668 b to communicate. Based on the disclosure and teachings provided herein, it should be noted that the number of bond wires and interconnects used in a die may vary depending on particular designs and/or applications.

FIG. 6C illustrates a semiconductor package 680 which is similar to that shown in FIG. 6B, except that edges 684 a-1, 684 b-1 of first and second die frames 684 a, 684 b are inside of edges 688 a-1, 688 b-1 of first and second dies 688 a, 688 b respectively. The edge locations of the semiconductor package 680 are similar to those of the semiconductor package 510 as shown in FIG. 5B. By having the edges 684 a-1 and 684 b-1 of the first and second die frames 684 a and 684 b behind the respective edges 688 a-1 and 688 b-1 of the first and second dies 688 a and 688 b, the first and second dies 688 a and 688 b can be moved closer to each other vis-à-vis the first and second dies 668 a and 668 b as shown in FIG. 6B, thereby allowing the bond wires 620 c-f to be closer as well. By having the bond wires 620 c-f closer, higher inductive or magnetic coupling can be achieved. Based on the disclosure and teachings provided herein, it should be understood that the distance between the first and second dies 688 a and 688 b may vary depending on a particular design or application.

FIG. 7 illustrates a method 700 for transmitting signals between a first die (e.g., first die 208 a) and a second die (e.g., second die 208 b) included in a semiconductor package (e.g., semiconductor package 200 and/or 500). The method 700 includes, at 704, providing an inductor arrangement that inductively couples the first die 208 a and the second die 208 b, while maintaining electrical isolation between the active circuit components of the first die 208 a and the active circuit components of the second die 208 b, where the inductor arrangement includes a first inductor circuit and a second inductor circuit. For example, as previously described, bond wires 220 a and 220 d, and interconnect 224 b form the first inductor circuit. Bond wires 220 b and 220 c, and interconnect 224 a form the second inductor circuit.

The method further comprises, at 708, transmitting a first signal from the first die 208 a (e.g., from terminals A and A′) through the first inductor circuit, such that a second signal is inductively generated in the second inductor circuit. Generation of the second signal is based on transformer action between the first inductor circuit and the second inductor circuit.

The method further comprises, at 712, receiving the second signal in the second die 208 b (e.g., in terminals B and B′ of the second die 208 b), where the second signal is representative (e.g., proportional) of the first signal. Thus, the first signal is transmitted from the first die 208 a, through the inductor arrangement, to the second die 208 b in the form of the second signal (as the second signal is representative of the first signal).

FIG. 8 illustrates a method 800 for transmitting signals between a first die (e.g., first die 208 a) and a second die (e.g., second die 208 b) included in a semiconductor package (e.g., semiconductor package 200 and/or 500). The method 800 includes, at 804, attaching a first bond wire (e.g., bond wire 220 a) between a first connector (e.g., connector 210 a) in the first die 208 a and a second connector (e.g., connector 212 a) in the second die 208 b, attaching a first interconnect (e.g., interconnect 224 b) between the second connector 212 a and a third connector (e.g., connector 212 d) in the second die 208 b, and attaching a second bond wire (e.g., bond wire 220 d) between the third connector 212 d and a fourth connector (e.g., connector 210 d) in the first die 208 a. The second connector 212 a, the third connector 212 d and the first interconnect 224 b are electrically isolated from active circuit components of the second die 208 b.

The method further comprises, at 808, attaching a third bond wire (e.g., bond wire 220 b) between a fifth connector (e.g., connector 212 b) in the second die 708 b and a sixth connector (e.g., connector 210 b) in the first die 208 a, attaching a second interconnect (e.g., interconnect 224 a) between the sixth connector 210 b and a seventh connector (e.g., connector 210 c) in the first die 208 a, and attaching a fourth bond wire (e.g., bond wire 220 c) between the seventh connector 210 c and an eighth connector (e.g., connector 212 c) in the second die 208 b. The sixth connector 210 b, the seventh connector 210 c and the second interconnect 224 a are electrically isolated from active circuit components of the first die 208 a, as previously described. The third bond wire 220 b, the second interconnect 224 a and the fourth bond wire 220 c form a second inductor circuit.

FIG. 9 illustrates a method 900 for transmitting signals between a first die (e.g., first die 208 a) and a second die (e.g., second die 208 b) included in a semiconductor package (e.g., semiconductor package 200 and/or 500). The method 900 includes, at 904, providing an inductor arrangement that inductively couples the first die 208 a and the second die 208 b, while maintaining electrical isolation between the active circuit components of the first die 208 a and the active circuit components of the second die 208 b, where the inductor arrangement includes a first inductor circuit and a second inductor circuit. The method further comprises, at 908, transmitting a first signal during a first plurality of time slots from the first die 208 a (e.g., from terminals A and A′) through the first inductor circuit, such that a second signal is inductively generated in the second inductor circuit. The method further comprises, at 912, receiving the second signal in the second die 208 b (e.g., in terminals B and B′ of the second die 208 b), where the second signal is proportional to the first signal. The method further comprises, at 916, transmitting a third signal during a second plurality of time slots from the second die through the second inductor circuit, such that a fourth signal is inductively generated in the first inductor circuit, where the first plurality of time slots and the second plurality of time slots are interleaved. The method further comprises, at 920, receiving the fourth signal in the first die, wherein the fourth signal is proportional to the third signal.

FIG. 10 illustrates a method 1000 for transmitting signals between a first die (e.g., first die 208 a) and a second die (e.g., second die 208 b) included in a semiconductor package (e.g., semiconductor package 200 and/or 500). The method 1000 includes, at 1004, providing an inductor arrangement that inductively couples the first die 208 a and the second die 208 b, while maintaining electrical isolation between the active circuit components of the first die 208 a and the active circuit components of the second die 208 b, where the inductor arrangement includes a first inductor circuit and a second inductor circuit. The method further comprises, at 1008, transmitting a first signal, having a first frequency, from the first die through the first inductor circuit, such that a second signal is inductively generated in the second inductor circuit. The method further comprises, at 1012, receiving the second signal in the second die, wherein the second signal is proportional to the first signal. The method further comprises, at 1016, transmitting a third signal, having a second frequency, from the second die through the second inductor circuit, such that a fourth signal is inductively generated in the first inductor circuit, where the first signal and the third signal are transmitted substantially simultaneously. The method further comprises, at 1020, receiving the fourth signal in the first die, wherein the fourth signal is proportional to the third signal.

The method further comprises, at 812, transmitting a first signal from the first die 208 a through the first inductor circuit (e.g., from terminals A and A′). The method further comprises, at 816, inductively generating a second signal in the second inductor circuit based at least in part on transmitting the first signal through the first inductor circuit. Generation of the second signal is based on transformer action between the first inductor circuit and the second inductor circuit. The method further comprises, at 820, receiving the second signal in the second die 208 b (e.g., in terminals B and B′ of the second die 208 b), where the second signal is representative (e.g., proportional) of the first signal. Thus, the first signal is transmitted from the first die 208 a, through the first inductor circuit and the second inductor circuit, to the second die 208 b in the form of the second signal (as the second signal is representative of the first signal).

Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art and others, that a wide variety of alternate and/or equivalent implementations may be substituted for the specific embodiment illustrated and described without departing from the scope of the present invention. This present invention covers all methods, apparatus, and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifested and intended that the invention be limited only by the claims and the equivalents thereof. 

What is claimed is:
 1. A semiconductor package comprising: a first die; a second die; and an inductor arrangement configured to inductively couple the first die and the second die while maintaining electrical isolation between active circuit components of the first die and active circuit components of the second die.
 2. A method of transmitting signals between a first die and a second die included in a semiconductor package, the method comprising: providing an inductor arrangement that inductively couples the first die and the second die, while maintaining electrical isolation between active circuit components of the first die and active circuit components of the second die, wherein the inductor arrangement includes a first inductor circuit and a second inductor circuit; transmitting a first signal from the first die through the first inductor circuit such that a second signal is inductively generated in the second inductor circuit; and receiving the second signal in the second die, wherein the second signal is representative of the first signal. 